The present invention provides a light-weight, compact device for lighting discharge lamps, which is able to light discharge lamps to a stable condition without the use of a large-sized ballast of a heavy weight and large volume, and which is able to prevent damage to filaments in a discharge lamp, to thereby lengthen the life-time of the discharge lamps.
In a conventional discharge lamp lighting device, a ballast is inserted between the power supply terminals and the discharge lamps, so that a predetermined voltage is applied to the discharge lamps. However, since such a ballast is weighty and large-sized, a conventional discharge lamp lighting device itself has to also be formed in a large-size to accomodate the ballast. Because of their large-sized construction, discharge lamp lighting appliances are restricted by design, thereby no free choice in designing is available.
It is an object of the present invention to provide a lightweight and small-sized device for lighting discharge lamps to a stable condition without the use of a weighty and large-sized ballasts.
It is another object of the present invention to eliminate large noise signals, the necessity of the use of oscillation circuits capable of supplying large outputs resulting in expensive and large-sized lighting devices.
It is further object of the present invention to prevent damage to filaments in discharge lamps, thereby to lengthen the life-time of discharge lamps, by using a low-voltage output oscillation circuit and superposing the low-voltage output from the oscillation circuit on a commercial alternating current voltage.
It is still a further object of the present invention to reduce the number of polarity changes in the lamp energizing voltage as compared to the high-frequency, hign-voltage voltage drivers of the prior art to the number of polarity changes of the alternating current voltage.